Far be it from me to defend Sit Up but I suspect presenters from all shopping channels are not averse to inventing stories to support the sale of a product.
However, I could be wrong but I honestly doubt there are many who would actually invent people and keep up the story for years. I know Larry Grayson had an array of 'friends' like Everard and Slack Alice but you were never under any illusion they were just part of his act and he was making them up.
But there's a certain someone who clearly copies his act, badly, but would genuinely have us believe his friends really do exist but not only that, they place orders. I would politely remind that person that Larry had almost totally retired that kind of act by the late 1980's with only occasional outings, no doubt to keep it's appeal.
A two bob, very ex-Children's TV presenter rehashing it week in, week out on the most downmarket shopping channel around is lazy, and a good few decades behind the times.
Larry was very funny, and had more charm and warmth in his stringed spectacles than Dirty Peter but he was definitely of his time. It's 2013, that seems lost on the 'star' of Sit Up but it does give a clue to the age of customer his 'performance' is aimed at.